1. Field of the Invention
The present invention relates to a method for producing an integrated device. In particular, the invention involves the preparation of a single integrated device containing a plurality of passive elements.
2. Description of the Prior Art
In the conventional production of integrated devices, a variety of materials are required due to the diverse electrical properties of passive elements. However, it is difficult to control the heterogeneous boundary resulted from employing different materials. Particularly, sintering temperatures of materials vary from one another, which often causes failure during the integration process. Consequently, the production yield is adversely affected. Furthermore, ceramics are often utilized when producing passive elements, and the integration for ceramics is typically carried out using low temperature sintering to produce multi-layer structures. However, during the integration process, the passive elements are formed by thin films of ceramics, where the sintering temperature is usually greater than 850xc2x0 C., and the temperature of the substrate is greater than 600xc2x0 C. Therefore, it is very difficult to combine with the integration of multi-layer organic substrates.
Currently, an integration of electronic elements is carried out using thick-film or thin-film structures. However, heterogeneous boundary is even more complicated due to the diverse materials required to obtain different electronic characteristics. Especially when the optimized processing temperatures for various materials are not the same, the risks associated with both the difficulty and reliability for integrating a diversity of materials are relatively high. Furthermore, integration of non-linear elements, such as thermistors and varistors, is restricted in terms of the obtainable specifications and types due to the original characteristics of the materials. Properties of the products are somewhat unfavorably affected as well. As a result, it is an important task to develop an integration technique, which produces embedded passive elements at low temperature.
In order to overcome the above problems, the invention provides a method for producing a single integrated device containing a plurality of passive elements by modifying the electronic characteristics of the grain boundary. Resistors and capacitors with a wide range of specifications can be produced by adjusting the conditions of grain boundary. Particularly, using different grain boundary barriers and self-induced polarization in grains, non-linear elements, such as thermistors and varistors can be made.
The method for producing a single integrated device containing a plurality of passive elements comprises the steps of: providing a semiconductive ferroelectric substrate; applying diffusant onto the substrate; and thermally processing the substrate.
Another object of the invention is to provide a method for producing non-linear elements and resistors and capacitors on the same substrate using the same or different processing conditions. This allows the integration of passive elements by adjusting electronic characteristics of grain boundary of the substrate.
In addition, another object of the invention is to provide a process for integrating elements, without heating the whole substrate. This operating condition is advantageous to the production and application of burying various elements into a multi-layer printed circuits board. Meanwhile, an effective method for burying high dielectric constant (k) material into printed circuit boards is provided as well.